Gaming laptops are such a difficult thing to purchase. It seems like damned if you do and damned if you don't. Do you purchase one so powerful that it cannot be used on your lap? Do you purchase one that isn't so bulky so you can travel with it more frequently?
I have a hard time making decisions with computer hardware, and nVidia and AMD do not make this any easier. With their million different variations of GPUs and allowing them to be paired with inferior memory only complicates matters. Gee, did I get the 5850 with GDDR3 or GDDR5? Well, looky here, the performance difference can be greater than 20%.
Not all of this can be blamed on nVidia and AMD. The laptop manufacture decides to put in a uber GPU only to cripple it with a pathetic memory controller while not disclosing this fact. You have to hope someone else does a review and posts a GPUID screenshot.
I remember my DVT5 (awesome laptop BTW) which had a 9600M GT. Problem is, it was DDR2 @ 800Mhz while the DDR3 was 1400Mhz (I think?). Big difference. A 30% difference.
Anyway, back to the topic. I mention all of this, because I want to recomend that you check out a few websites.
www.notebookcheck.com and
www.notebookreview.com. Be sure that you read the forums at the latter and really research this purchase. Not all nVidia and AMD GPUs perform the same despite having the same model number. They play with the clocks, voltages and the memory types and speeds.